1. Field of the Invention
The invention relates to apparatus for chopping picture frame molding and more specifically to a measuring attachment for a standard miter chopper.
2. Description of the Prior Art
Miter choppers employed for chopping picture frame molding have essentially become standardized in their construction. The standard miter chopper employs two blades mounted at some predetermined included angle, e.g., 90.degree.. In use, it is necessary to measure off the length of molding to be cut and then a foot operated pedal linkage is used to bring both of the blades through the molding at the desired location to effect trailing and leading cuts. So far as is known, there are only two types of apparatus utilized for measuring off the length of molding to be cut. In one form of prior art measuring apparatus used on a standard miter chopper, a scale is scribed on the bed of the chopper at a 45.degree. angle to the front of the bed. The molding length is determined by aligning the point at which the inside of the rabbet and the mitered end of the molding intersect with the appropriate mark on the chopper bed scale, then sliding a movable stop along the front rail of the chopper until it abuts the end of the molding. While this is the most common method of determining molding length, difficulties of accurate measurement are frequently encountered in attempting to read a scale at a 45.degree. angle to the operator, graduated in one-eighth inch increments, and covering the full width, normally five and one-half inches, of the chopper bed.
In another type of measuring apparatus used on the standard miter chopper, a vernier arrangement composed of three scales is employed. The first of these scales is a molding width scale located near the chopper head and perpendicular to the front rail of the chopper bed. The first scale is used for determining molding width as measured from the back of the molding to the inside of the rabbet. The second scale is a standard inch scale affixed to the front rail of the chopper. The third scale is a vernier scale mounted on the movable stop. Thus, molding length is determined by first determining the molding width with the first scale, then lining up the corresponding mark on the third vernier scale with the desired molding length on the second inch scale mounted on the front rail. While this second form of prior art apparatus is more easily read than the first mentioned prior art measuring apparatus, users frequently encounter misreadings by virtue of the three scales involved.
Thus, it becomes the general object of the present invention to improve upon those prior art miter chopper measuring devices described above and particularly to simplify and make more accurate the measuring operation.